// Problem: 
// Contest: 
// URL: 
// Memory Limit: 
// Time Limit: 
// #pragma GCC optimize("Ofast")
// #pragma GCC optimize("unroll-loops")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
#include<bits/stdc++.h>
using namespace std;
#define int long long
inline int read(){
	int s=0,w=1;
	char ch=getchar();
	while(ch<'0'||ch>'9'){if(ch=='-')w=-1;ch=getchar();}
	while(ch>='0'&&ch<='9') s=s*10+ch-'0',ch=getchar();
	return s*w;
}
signed main()
{
	int t=1;
//	cin>>t;
	while(t--)
	{
		priority_queue<int,vector<int>,greater<int>> h[100010];
		int n,m,t;
		cin>>n>>m>>t;
		for(int i=1;i<=m;i++)
		{
			int x,y;
			cin>>x>>y;
			h[y].push(x);
		}
		int cnt=0;
		for(int i=1;i<=n;i++)
		{
			int pri=0;
			int lastget=0;
			bool in=0;
			while(!h[i].empty())
			{
				int x=h[i].top();
				h[i].pop();
				if(lastget!=x)pri-=(x-lastget-1);
				if(pri<0)pri=0;
				if(in&&pri<=3)in=false;
				pri+=2;
				lastget=x;
				if(pri>5)in=true;
			}
			if(lastget!=t)pri-=(t-lastget);
			if(in&&pri<=3)in=false;
			if(in)cnt++;
		}
		cout<<cnt;
	}
	return 0;
}
